The primary novelty of this invention is considered to be in its provisions for installing a new ribbon in the cartridge. The following references show such refillable cartridges, but are not otherwise notably similar to the embodiment of this invention. These references are the following: U.S. Pat. Nos. 3,260,344 to Doyle, 4,213,715 to Haftmann et al, 4,367,963 to Daughters, and 4,397,574 to Wojdyla.
The embodiment of this invention includes an endless belt ribbon feed. Comparable belt drives are shown in the following references none of which show refillable cartridges: U.S. Pat. Nos. 3,692,255 to Von Behren, 4,528,572 to Sasaki et al, and 4,629,346 to Surti and 4,685,817 to Surti. Since these cartridges are not refillable, they normally are discarded entirely when their ribbon has been used. This invention provides for the reuse of cartridges and thereby saves the costs of providing additional cartridges.
The preferred embodiment of this invention is symmetrical so that the cartridge can be turned over and the ribbon driven back the other way. This permits reuse of the cartridge parts with a double width ribbon and thereby provides a cost saving. Such reversibility is considered essentially conventional in this art. Illustrative of such reversibility and the general cartridge configuration of the preferred embodiment are the following: U.S. Pat. Nos. 4,496,255 to Meintrup et al, and 4,568,210 to Privitera and IBM Technical Disclosure Bulletin article entitled "Improved Capacity Typewriter Ribbon," Vol. 22, No. 8A, Jan. 1980 at P. 3469.